This invention relates to a connector structure for making connection to the individual conductors of a flat cable and more specifically relates to a novel connector structure having a generally D-shaped surface configuration.
D-type cable connectors are well known in the art and are shown, for example, in U.S. Pat. No. 3,930,708. Cable connectors of this type generally have piercing contacts for making piercing contact engagement with the individual conductors of a flat cable. These individual conductors are conventionally round in cross-section, but may also be rectangular or flat. These piercing contacts, hereafter referred to as the contact tail, are connected to pin-type regions, hereafter referred to as nose regions of the contact. The nose regions of each contact extend into a D-shaped shroud and can be plugged into a cooperating plug connector so that convenient connection can be made to the individual conductors of the flat cable. Connectors of this general type are sometimes called insulation displacement connectors (IDC).
In connectors of this type, the contact nose pins at the D face are commonly on 0.054 inch centers. The individual conductors of the flat cable, however, are commonly spaced on 0.050 inch centers. Thus, the problem exists of making electrical connection from the noses on one center spacing to the cable conductors on a different center spacing.
Numerous structures have been suggested in the past to solve this problem. For example, in one available connector the cable is split longitudinally before it is positioned within the connector so that the cable is formed into flat bundles of three or more bundles, each of which is spaced to be disposed over respective piercing contact tails which are on larger centers. However, since the cable conductors can be separated in bundles of three or more, it is possible to accommodate the bundles on 0.050 inch centers to the tails on 0.054 inch centers.
In another known arrangement, the flat cable is manufactured with short sections which are preformed on 0.054 inch centers interspersed in longer sections on conventional 0.050 centers. These short centers then mate directly onto the contact tails which are on 0.054 inch centers.
Another solution which has been used in the past is to use a contact structure having a piercing end and a nose end which are connected by two spaced bars. These two spaced bars are then laterally deflected as necessary to accommodate the lateral displacement between a particular conductor and a particular contact nose location for that cable on the base of the connector. With this type of arrangement, since each of the contact assemblies has a fixed length, the contact tails will have different heights within the connector, since those which have a smaller lateral offset from their nose end will have a higher position within the connector.
Other problems exist with prior art D-type connectors since the connector can make connection to the cable in only one of an open face connection or a close face connection. By open face is meant an arrangement wherein the cable is laid on top of physically accessible piercing contact tails and is then pressed by hand or with a tool onto the contact tails. The cable and contacts can then be visually inspected. In the closed face assembly, a cable is simply inserted between the piercing contact tails and a cover, which is loosely held onto the base and hides the cable and the contact tails. The cover is then pressed onto the connector and forces the cable conductors into respective piercing contact tails. The cover then latches onto the base and thus the pierced cable cannot be inspected. It is frequently desirable to use either an open or closed face arrangement for making contact between the cable conductors and the piercing contact tails.
The prior art has also provided arrangements for both plain covers and strain relief covers for ribbon cable connectors. A device of this type is shown, for example, in U.S. Pat. No. 3,355,699 dated Nov. 28, 1967. In devices of the type known, however, once the covers are connected, it is difficult if not impossible to disconnect them from the base.